Allow the mince to cook for 15-20min or until the liquids are reduced. After that mix in the parsley and set aside.
While the mince and pasta are cooking, use a separate pot that holds at least 2L of liquid and place it on a medium heat. Add the butter in the pot and allow it to completely melt.
I usually warm the milk in the microwave in the measuring jug for 3 minutes in 1 minute intervals. Saves me washing another pot but if you do not have a microwave then heat the milk on the stove, enough to be able to place your finger in without burning.
A cup is equal to 250mL, hence if you pour in a cup of milk each time you will have to repeat the process 5 times. Remember to allow the sauce to thicken each time before adding more milk and stirring often. As a time indication, it took me 12min to make this béchamel sauce.
If you struggle to remove the lumps in the béchamel sauce because you have not stirred it enough, then use a hand mixer to break them up.
I wrote specific amounts of halloumi to use at each stage but basically it is a whole block of 225g, which I grated and then split up the amounts to add at each stage.